from time import sleep


def sing():
    for i in range(3):
        print('正在唱歌...%d' % i)
        dance()
        sleep(1)


def dance():
    for i in range(3):
        print('正在跳舞...%d' % i)
        sleep(1)


if __name__ == '__main__':
    sing()
    # dance()
